期刊
ACS APPLIED MATERIALS & INTERFACES
卷 9, 期 47, 页码 41443-41453出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.7b13179
关键词
spintronics; quantum spin Hall effect; topological insulators; two-dimensional materials; first-principles calculations
资金
- NSFC [11434006, 11274143]
- NBRP of China [2013CB922303, 2015CB921502, B13029]
Knowledge about chemical functionalization is of fundamental importance to design novel two-dimensional topological insulators. Despite theoretical predictions of quantum spin Hall effect (QSH) insulator via chemical functionalization, it is quite challenging to obtain a high-quality sample, in which the toxicity is also an important factor that cannot be ignored. Herein, using first principles calculations, we predict an intrinsic QSH effect in amidogen-functionalized Bi/Sb(111) films (SbNH2 and BiNH2), characterized by nontrivial Z(2) invariant and helical edge states. The bulk gaps derived from p(x,y) orbitals reaches up to 0.39 and 0.83 eV for SbNH2, and BiNH2 films, respectively. The topological properties are robust against strain engineering, electric field, and rotation angle of amidogen, accompanied with sizable bulk gaps. Besides, the topological phases are preserved with different arrangements of amidogen. The H-terminated SiC(111) is verified as a good candidate substrate for supporting the films without destroying their QSH effect. These results have substantial implications for theoretical and experimental studies of functionalized Bi/Sb films, which also provide a promising platform for realizing practical application in dissipationless transport devices at room temperature.
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